Bilateral Versus Unilateral Lymph Node Dissection in High-Risk Prostate Cancer (BALANCE)

Inclusion criteria

• Male patients aged 18 years or older
• Histologically confirmed unilateral high-risk localized prostate cancer, defined by at least one of the following: ISUP Grade Group 4 or 5; suspicion of at least cT3a disease on multiparametric MRI and/or PSMA PET; or PSA greater than or equal to 20 ng/mL with a unilateral index lesion
• Unilateral features of the index lesion defined by biopsy, multiparametric MRI, and PSMA PET
• No PSMA PET-positive pelvic lymph nodes contralateral to the dominant side of the prostate cancer
• No significant contralateral PSMA uptake on the non-dominant side, defined as lesions with PRIMARY score 3 to 5
• No contralateral index lesion on multiparametric MRI subsequently confirmed by prostate biopsy
• No high-risk histology on the side contralateral to the dominant lesion, including ISUP Grade Group greater than 3 or unconventional prostate cancer histology
• No frank extracapsular invasion or seminal vesicle invasion on the contralateral side
• Up to two positive systematic cores with unfavorable intermediate-risk disease or up to four with favorable intermediate-risk disease are allowed on the contralateral side
• A maximum of two pelvic PSMA-positive lymph nodes allowed on the dominant side
• Clinically localized disease, defined as less than cT4 on multiparametric MRI and no distant metastases, including no retroperitoneal lymph nodes on PSMA PET
• Life expectancy greater than 10 years according to physician judgment
• Scheduled for robot-assisted radical prostatectomy and fit for surgery
• Written informed consent provided

Exclusion criteria

• Any prostate cancer treatment prior to prostatectomy, including androgen deprivation therapy, neoadjuvant chemotherapy, radiotherapy, or focal ablative therapy
• Prior active treatment for prostate cancer
• Contralateral ISUP Grade Group 4 to 5 prostate cancer
• Contralateral ISUP Grade Group 2 in more than 4 positive cores or ISUP Grade Group 3 in more than 2 positive cores
• Contralateral cT3 disease on multiparametric MRI
• N1 or M1 disease on PSMA PET or multiparametric MRI, except for up to two positive pelvic lymph nodes on the dominant side
• No systematic prostate biopsies performed, with a minimum of 10 cores, and targeted biopsies when a target lesion is present
• Other active malignancy
• Contraindication to multiparametric MRI and/or PSMA PET
• Inability to provide written informed consent
• Age younger than 18 years
• ASA score greater than 3
• Any contraindication to pelvic lymph node dissection
• Severe psychiatric disease
• Inadequate hematologic and/or coagulation function
• Active infection
• Any other serious medical, psychiatric, psychological, familial, or geographic condition that, in the judgment of the investigator, may interfere with staging, treatment, follow-up, compliance, or increase treatment-related risk
• Patients with prior malignancy treated with curative intent are eligible only with mandatory approval by the local multidisciplinary tumor board